If further climate outcomes continue to track Hansen's thus-far correct 35-year-old predictions [1], then we've already passed some kind of tipping point and "the heat death of everything" could potentially mean Venusian-style anthropogenic cooking of Earth in some worst-case scenarios, and mass population dislocations and mega-scale environmental disruptions in milder scenarios.
If it turns out that life as we know it is exceedingly rare (and I must admit that the more we find out about exoplanets, the more disconcerted I am while realizing that the hazy possible solution space to the Fermi Paradox is becoming rather uncomfortable as the resolution grows with each passing decade), then that would be truly a tragic outcome.
I believe GP was referring to the heat death of the universe [0], which might be paraphrased as the death of heat in the universe, rather than lifeforms on one planet dying when the environment becomes too hot for said lifeforms to survive.
I should have been clearer; I trying to note the irony of saying "heat death of everything" could be a much shorter timeframe than we usually mean when we say that phrase, if Hansen's forecasts turn out correct.
If further climate outcomes continue to track Hansen's thus-far correct 35-year-old predictions [1], then we've already passed some kind of tipping point and "the heat death of everything" could potentially mean Venusian-style anthropogenic cooking of Earth in some worst-case scenarios, and mass population dislocations and mega-scale environmental disruptions in milder scenarios.
If it turns out that life as we know it is exceedingly rare (and I must admit that the more we find out about exoplanets, the more disconcerted I am while realizing that the hazy possible solution space to the Fermi Paradox is becoming rather uncomfortable as the resolution grows with each passing decade), then that would be truly a tragic outcome.
[1] https://tamino.wordpress.com/2016/08/16/crystal-serenity/